Bear with BimmerBoost for a moment. While the M340i includes the letter M in the name it is actually an M-Sport model and not an official BMW M model such as the M3. Does that make sense? A bit confusing with how BMW puts the letter M on everything now but the point is the new G20 M340i is powerful.

For context, the M340i is making more power than the BMW E46 M3 CSL. Despite its horsepower rating, BimmerBoost would bet dyno output will show the updated B58 is close to the E92 M3's output of 414 horsepower. That means roughly in the ~350 to the wheels range.

That makes for a hell of a 3-Series. Well, if you are not in the European market. Emissions regulations choke the B58 down to 355 horsepower for European Union members. Hah.

As for what changes BMW made for the increase from 335 horsepower, we will have to wait and see. Odds are BMW simply changed the tuning but if there is a bigger turbocharger on there the G20 M340i B58 will be, well, the new N54.

The new N54 except with better cooling and a closed deck block mated to a better transmission in a new, lighter, and much stiffer chassis. Sounds like progress, doesn't it?

The new power unit’s standout features include a water-cooled exhaust manifold integrated into the cylinder head, sharper turbocharger response and superior acceleration, and direct injection technology which now works at increased maximum pressure of 350 bar.

Here is the setup in the new X5. RealOEM names it B58C, but they usually refer to engines differently. Anyhow, i guess the whole B58 will soon switch to this design known as B58B30M1. The 380hp models will get the B58B30O1 which i guess will have bigger turbo based on the press releases i've seen so far. Unless BMW pull a Benz thing and lie about using bigger turbo.

For the record, “Integrated into the head” likely means the turbo bolts directly to the cylinder head. The manifold passages would be cast into the head itself. The effectiveness of turbo upgrades will be limited to the flow characteristics of that internal manifold (i.e. no way to upgrade to a tubular manifold or larger cast manifold).

EDIT: Looks like someone beat me to it with a picture. As you can see, there’s no manifold to really improve upon (other than a little bit of porting). Hopefully the flow characteristics of those passages are good.

For the record, “Integrated into the head” likely means the turbo bolts directly to the cylinder head. The manifold passages would be cast into the head itself. The effectiveness of turbo upgrades will be limited to the flow characteristics of that internal manifold (i.e. no way to upgrade to a tubular manifold or larger cast manifold).

EDIT: Looks like someone beat me to it with a picture. As you can see, there’s no manifold to really improve upon (other than a little bit of porting). Hopefully the flow characteristics of those passages are good.

So we're going to need to see aftermarket manifolds to get real turbo upgrades?

At least they're bolting it to the head and not casting it into the head.

So we're going to need to see aftermarket manifolds to get real turbo upgrades?

At least they're bolting it to the head and not casting it into the head.

It looks like they are casting it into the head. Based on that photo, there are only 2 exhaust ports. One for the front 3 cylinders and one for the back 3 cylinders. The only aftermarket “manifold” they will be able to build is a little Y-pipe to adapt different turbos. That should work just fine (and likely be really easy to do), but how well will those integrated passeges in the head flow above stock power levels? Hopefully pretty well. Either way, it probably won’t be an issue for mild turbo upgrades.

It looks like they are casting it into the head. Based on that photo, there are only 2 exhaust ports. One for the front 3 cylinders and one for the back 3 cylinders. The only aftermarket “manifold” they will be able to build is a little Y-pipe to adapt different turbos. That should work just fine (and likely be really easy to do), but how well will those integrated passeges in the head flow above stock power levels? Hopefully pretty well. Either way, it probably won’t be an issue for mild turbo upgrades.

So we're limited with hybrid until what? An aftermarket cylinder head?

It looks like they are casting it into the head. Based on that photo, there are only 2 exhaust ports. One for the front 3 cylinders and one for the back 3 cylinders. The only aftermarket “manifold” they will be able to build is a little Y-pipe to adapt different turbos. That should work just fine (and likely be really easy to do), but how well will those integrated passeges in the head flow above stock power levels? Hopefully pretty well. Either way, it probably won’t be an issue for mild turbo upgrades.